Lummi Nation Nooksack River Basin Salmonid Population Assessments, FY21

Two rotary smolt traps will be operated in the Nooksack River, one in the lower mainstem (which has been operated since 1994) and one in the South Fork. The additional smolt trap in the South Fork will expand our ability to calculate outmigration survival and aid in expanding mark/recapture estimates based on PIT tagging data. Fishery biologists and technicians will operate both traps during the principal outmigration period from approximately January to August. Additional beach seine sampling near the lower mainstem trap site will be conducted to improve smolt production estimates and sample a wider spectrum of outmigrant size classes. This additional sampling also helps improve sample size for DNA collection to enumerate differences in population and origin productivity (i.e. Hatchery vs. wild origin; North Fork/Middle Fork vs. South Fork population). Production estimates will be made for Chinook, Steelhead, Coho and other salmonids from modeled expansion of trap catches.



Field staff will participate in co-manager spawning ground surveys in South and Middle Forks of the Nooksack River with emphasis on Chinook salmon. River water temperature, turbidity, discharge, and stage height are monitored to help interpret survey results and to assist with field scheduling. Spawner survey data will be shared with other co-managers to develop Chinook escapement estimates using a traditional approach based on visual redd and fish carcass counts. Ongoing genetic mark-recapture escapement techniques using DNA data collected from spawner carcasses and smolt trap outmigrants will be compared with methods that rely on visual counts.



For both projects, fish lengths and analysis of scales, otoliths, and DNA tissue samples provides information on age, stock composition, and life history types needed for refinements in adult escapement and smolt production estimates. Field staff time to collect this information is included in this proposal. Professional staff will utilize data collected from the monitoring element of the project and other independent data sources to increase the precision and accuracy of models used to develop adult escapement and smolt production estimates.



To supplement data needed for production and escapement estimates, additional beach seine sampling may be used in the river, estuary, and adjacent nearshore areas as resources permit. In coordination with a separate grant-funded project, environmental monitoring of sea surface temperature (SST), salinity and dissolved oxygen (DO) will help us to interpret the catch data and possibly link these data to climate change factors. Monitoring presence of predator, competitor, and prey species in the catch may provide insight into factors affecting migratory timing, life-history types present, rearing densities, habitat utilization, and co-occurrence of stocks from the Nooksack and other watersheds.

The goal of this project is to improve the quality and accuracy of salmonid escapement, production, and habitat use with a focus on Chinook. A secondary goal is to identify constraints preventing recovery of the stocks. This work is to evaluate and adaptively improve methods for salmonid population baseline data acquisition and estimates required for: 1) ESU reporting, 2) forecasting/management, 3) stock identification and aging, 4) evaluation of survival, restoration, and hatcheries, 5) other research including impacts of climate change or identifying limiting factors. A secondary objective is to utilize these data in a life history model and framework for Nooksack early Chinook, which is currently in development (funded separately).



The expected benefits of providing more accurate and complete population estimates and habitat use for adults and juveniles are: 1) evaluation and identification of restoration activities that will have or could have the largest impact on recovery, 2) improved ability to identify factors limiting recovery, such as predation or toxicity that habitat restoration cannot address and that may require other actions or solutions.